Leg exerciser

ABSTRACT

An exercise apparatus is used for leg exercises, and particularly for exercising the muscles used in ice skating. The apparatus has a frame with two four bar linkages arranged side by side. Each linkage carries a foot pad. A resistance unit is attached to each linkage to resist movement of the linkage in both directions. The resistance unit is preferably a double acting hydraulic cylinder connected to variable flow control valves to vary the resistance to linkage movement.

The present invention relates to exercise apparatus of the typecomprising:

a frame;

two first arms pivotally connected to the frame;

two second arms pivotally connected to respective ones of the first armsat positions spaced from the connections of the first arms to the frame;

two tie rods, each pivotally connected to the frame and a respective oneof the second arms so as to provide, with the first and second arms andthe frame, two four bar linkages;

a foot pad mounted on each second arm; and resistance means forresisting pivotal movement of each first arm with respect to the frame.

An apparatus of this type is disclosed in Canadian Patent 955,278,issued Sep. 24, 1974 to George V. Hague. The disclosed apparatus isintended to allow simulation of the leg movements in ice skating, withthe apparatus applying resistance to a rearward push by the foot on afoot pad. In this known apparatus, the resistance acts only against therearward movement of a foot pad, so that there is little effect inexercising the opposing muscle groups used in a forward stride. Inaddition, there is no provision made in the known device for adjustingthe magnitude of the resistance. This limits both the training andtherapeutic value of the apparatus.

The present invention is intended to address these deficiencies of theknown device. Preferred embodiments of the invention are intended toprovide additional improvements in other areas.

According to the present invention there is provided an apparatus of theaforementioned type that is characterized in that the resistance meansis a double acting resistance means for resisting pivotal movement ofeach first arm with respect to the frame in both directions, and meansare provided for adjusting resistance to movement provided by theresistance means.

The resistance means may, for example, be a double acting fluid cylinderwith a cylinder barrel, a piston in the barrel and a piston rodextending from the piston through one end of the barrel. Fluid inlets tothe barrel adjacent each end are equipped with one-way inlet valves,while outlets, also adjacent the ends of the barrel are connected tovariable flow control valves for controlling the resistance to movement.

In an hydraulic system, a fluid reservoir may be provided by a tubesurrounding the cylinder barrel, with the inlets communicating directlywith the reservoir and return flow from the control valves discharginginto the reservoir.

One particularly advantageous embodiment has the flow control valvesmounted on a handle bar standard for ready access by a person using theapparatus.

The apparatus may also include adjustable stop means for varying stridelength by varying the travel limits of the linkage. In one preferredform, the stop means is an adjustable stop projecting into one end ofthe resistance cylinder to limit piston travel.

The apparatus may also include a novel foot pad in which a sole platecarrying foot or shoe retainers is mounted rotatably on a support arm bya resilient pedestal. The support arm is itself aligned with andpivotally connected to the respective second arm to pivot upwards abouta horizontal axis, transverse to the second arm. This arrangement allowsthe foot universal rotation on the support arm against the resistance ofthe pedestal. The foot may be lifted at the end of a rearward movementand during a forward movement, as in normal skating.

The geometry of the preferred embodiment has the pivot mountings betweenthe first arm and the frame and between the tie rod and the frame spacedslightly and side by side. The pivotal connection of the tie rod to thesecond arm is approximately midway between the pivotal connectionbetween the first and second arms and the foot pad. This produces amovement that is closer to a natural skating action than is the casewith the known apparatus.

A further desirable feature is a handle bar for the apparatus, to begripped by a user. The most preferred handle bar is one that can beadjusted fore and aft of the frame for the comfort of the user.

In the accompanying drawings, which illustrate exemplary embodiments ofthe present invention:

FIG. 1 is a perspective view of an exercise apparatus according to theinvention;

FIG. 2 is a plan view of the apparatus of FIG. 1, omitting the uppersection of the handle bar;

FIG. 3 is a section along line III--III of FIG. 2;

FIG. 4 is an illustration of the resistance system with the hydraulicfluid reservoir tube shown in section;

FIG. 5 is a longitudinal section of the resistance cylinder;

FIG. 6 is a schematic view of an alternative fluid circuit; and

FIG. 7 is a side elevation of a foot pad.

Referring to the accompanying drawings, especially to FIGS. 1 and 2,there is illustrated an exercise apparatus 6 that includes a frame 8 inthe form of a relatively wide U-shaped box section beam with two arms 10and a centre section 12 extending between them. Each of the arms carriesa pair of lugs 14 projecting to centre of the U-shaped frame adjacentthe front. Each pair of lugs 14 carries a first arm 16 that is connectedto the associated lugs by a vertical pivot 18. Each first arm has anouter end 20 and an inner end 22 that meet at an obtuse angled bend 24.

At the innermost end of the arm are two vertically spaced lugs 26 thatare pivotally connected to a second arm 28 by a vertical pivot pin 30.The second arm 28 is straight. Its outer end slopes downwardly andterminates at the bottom in a support plate 34 that engages the undersurface of a support arm 36 projecting from the end of the second arm.The end of the support arm has two lugs 38 positioned on opposite sidesof the second arm 28 and connected to it by pivot pin 40. The outer endof the support arm 36 caries a foot pad 42.

Two tie rods 44 are connected to the frame by pivots 46 locatedlaterally to the outside of the pivots 18. Each tie rod has an outer end48 and an inner end 50 meeting at an obtuse angled bend 52. The innerend 50 of each tie rod is pivotally connected to a respective one of thesecond arms 28 by a pivot pin 54. This is located adjacent a pointmidway between the pivot 30 and the foot pad 42. This produces a fourbar linkage, including the first arm 16, the second arm 28, the tie rod44 and the section of frame between the tie rod and first arm pivots 46and 18 respectively. The Geometry of this linkage causes the linkage toswing between the forward positions illustrated in solid line in FIG. 2and the broken line position illustrated in broken line in FIG. 2. Aswill be observed, the foot pad moves in an arc to the rear and theoutside during this movement. This simulates the actual path of footmovement during ice skating.

To provide resistance to leg movement, two resistance units 56 areincluded in the apparatus. Each of these has a head 58 on one endengaged with two pins 60 that are in turn pivotally engaged with twolugs 62 projecting inwardly from a respective side arm 10 of the frame8. A piston rod 64 projects from the other end of the resistance unitand is connected to two lugs 64 on the inner end 22 of a respectivefirst arm 16 by a pivot pin 68.

Also mounted on the frame is a handle bar 70. This includes a standard72 projecting upwardly from the centre section 12 of the frame 8. Abracket 74 mounted on the frame is connected to the standard through apivot 76 and an adjusting unit including a nut 78 carried by the lowerend of the standard and a screw 80 engaged with a nut and mountedrotatably on the bracket. An adjustment knob 82 on the outside of thebracket is used for rotating the screw. Part way up the standard 72 is aconsole 84 that carries two resistance adjustment knobs 88 that serve,as described in the following, to adjust the resistance to movementprovided by the resistance units 56. At the top of the standard is ahand grip 90. The hand grip can be adjusted fore and aft with respect tothe frame by rotating the knob 82 to drive the nut 78 along the .screw80 and tilt the standard 72 around the pivot 76.

The frame 8 is mounted on non-slip feet 92 that hold the apparatus inplace while it is being used.

The construction and operation of each of the resistance units is mostclearly illustrated in FIGS. 4 and 5. Each unit includes an hydrauliccylinder 93 including a cylinder barrel 94. The barrel is surrounded bya reservoir tube 96 closed at the ends by end plates 97. Near the endsof the cylinder barrel are respective fluid inlets 98 and 100 andrespective outlets 102 and 104. The outlets 102 and 104 dischargethrough respective check valves 106 and 108 into a common line 110leading to a flow control valve 102. The valve is of a known type thatprovides variable restriction to the through flow of hydraulic fluid.The valve 112 discharges into a return line 114 leading to the reservoircontained between the tube 96 and the cylinder barrel 94.

As illustrated most particularly in FIG. 5, the inlet 98 is equippedwith a one-way or check valve 116. This includes an internal valve seatand a ball 120 that engages with the seat to prevent fluid flow from thecylinder barrel out of the inlet 98. The ball is retained in the inletby a sleeve 122 that is engaged in the end of the cylinder barrel and issealed to the piston rod 64 by seals 126.

The cylinder inlet 100 is likewise equipped with a one-way valve 127that includes an internal valve seat 128 and a ball 130 that engages theseat to prevent flow from the inlet 100. The ball is retained in theinlet by a sleeve 132 projecting axially along the cylinder barrel 94from the head 58.

A stride length adjuster 134 extends through the head into the cylinderbarrel. This includes a rod 136 extending axially through the head andhaving an internal piston engaging head 138. A threaded section 140 ofthe rod engages a mating thread in the bore through the head 58 so thatrotation of the rod will advance or retract the piston engaging head 138in the cylinder barrel. Rotation of the rod is accomplished with a handknob 142 mounted on the outer end of the rod. A seal 144 is engagedbetween the rod and the head to prevent fluid leakage from the cylinder.By adjusting the stroke limits of the piston, the stride length of thelinkage is also controlled.

The embodiment of the invention illustrated in FIGS. 1 and 4 includes asingle control valve for each resistance unit 56. Adjustment of thecontrol valve adjusts the resistance of the unit to movement in bothdirections. On movement in a rearward direction, the piston 124 isdriven towards the head 58 and drives fluid from the outlet 104, throughthe check valve 108 and the flow control valve, back to the reservoir.At the same time, fluid is drawn into the cylinder barrel on theopposite side of the piston, through inlet 98 and check valve 106. Onthe return stroke, the piston drives fluid out of the outlet 102,through the check valve 106 and the flow control valve 112 to thereservoir. It will be noted from FIG. 5 that the piston rod is fairlylarge in diameter, so that the actual force required to complete thereturn stroke is significantly less than the force required on therearward stroke. This is in keeping with the efforts required in normalskating.

For some purposes, it may be desirable to provide for independentcontrol of the force required to complete rearward and forward strides.This may be achieved using a fluid circuit as illustrated in FIG. 6.This circuit provides a supply line 146 leading from the cylinder outlet104 to a flow control valve 148 and a separate supply line 150 leadingfrom the cylinder outlet 104 to an independent flow control valve 152.The two control valves discharge into a common return line 154 to thereservoir. In this circuit, the two control valves 148 and 152 areindependently adjustable to alter the resistance to the forward andreturn strokes.

A foot pad assembly for the apparatus is illustrated in FIG. 7. Theassembly 156 includes the support arm 36 which is illustrated as havingan upturned end 160. A resilient elastomeric pedestal 162 is mounted onthe support arm 36 immediately in front of the upturned end 160. It issecured in place using a stud 164 and a nut 166. A sole plate 168 of thefoot pad is mounted on the top end of the pedestal. To the rear of thepedestal, the sole plate has an-abutment 170 that engages the upturnedend of the support arm 36 to limit the downward movement of the heel ofthe foot pad. The sole plate carries an integral heel cup 172 and a toestrap 174 that is adjustable to grip shoes of different sizes.

In use of the apparatus, a user straps his feet into the foot pads andgrasps the handle bars. The handle bars may be adjusted fore and aft tosuit the stature or comfort of the user. The stride length may also beadjusted using the adjustment knobs 142 on the resistance units 56. Thefeet are then moved fore and aft alternately to follow a natural skatingmotion against the resistance of the resistance units. This resistancecan be adjusted as necessary or desired using the adjustment knobs 86 onthe console 84. It will therefore be seen that the present inventionprovides an apparatus that is particularly effective as a leg exercisingdevice and particularly for exercising those muscles used in iceskating. Because of the adjustability of the apparatus, it is suited toalmost any individual and may be used for progressive training ortherapy as desired.

While particular embodiments of the present invention have beendescribed in the foregoing, it is to be understood that otherembodiments are possible within the scope of the invention. Theinvention is to be considered limited solely by the scope of theappended claims.

We claim:
 1. An exercise apparatus comprising:a frame; two first armspivotally connected to the frame; two second arms pivotally connected torespective ones of the first arms at positions spaced from theconnections of the first arms to the frames; two tie rods, eachpivotally connected to the frame and a respective one of the second armsso as to provide, with the first and second arms and the frame, two fourbar linkages; a foot pad mounted on each second arm; and resistancemeans comprising two fluid cylinders, each connected between the frameand a respective one of the first arms for resisting pivotal movement ofeach first arm with respect to the frame, each fluid cylinder being adouble acting cylinder comprising:a cylinder barrel; fluid port means ateach end of the cylinder barrel; one-way valve means communicating witheach fluid port means for passing fluid into the cylinder barrel andpreventing fluid flow from the cylinder barrel; adjustable control valvemeans connected to the fluid port means for controllably restrictingflow from the fluid port means; a piston slideable in the barrel and apiston rod secured to the piston and projecting from one end of thebarrel; means for pivotally connecting the cylinder to the frame andmeans for pivotally connecting the piston rod to the associated firstarm; stop means for limiting the stroke of the piston in the cylinderbarrel, the stop means, comprising a rod projecting into the cylinderbarrel from an end thereof opposite the piston rod for engagement withthe piston.
 2. An apparatus according to claim 1 wherein the cylinder isan hydraulic cylinders.
 3. An apparatus according to claim 2 including areservoir for hydraulic fluid.
 4. An apparatus according to claim 3wherein the one-way valve means communicate between the associated fluidport means and the reservoir.
 5. An apparatus according to claim 4wherein the control valve means are connected to the fluid port meansand the reservoir.
 6. An apparatus according to claim 5 wherein the flowcontrol valve means comprise a single adjustable restrictor valveconnected to the fluid port means at both ends of each cylinder barreland one-way valves passing fluid from the port means to the adjustablerestrictor valve and preventing flow from the restrictor valve to theport means.
 7. An apparatus according to claim 6 wherein the flowcontrol valve means comprise two independently adjustable restrictorvalves connected to the respective fluid port means at opposite ends ofeach cylinder barrel.
 8. An apparatus according to claim 3 wherein thereservoir comprises a tube surrounding the cylinder barrel.
 9. Anapparatus according to claim 4 including handle bars comprising astandard projecting upwardly from the frame, wherein the flow controlvalve means are mounted on the standard.
 10. An apparatus according toclaim 1 including handle bars comprising a standard projecting upwardlyfrom the frame and hand grips on the standard, characterized by meansfor adjusting the inclination of the standard with respect to the frame.11. An apparatus according to claim 1 including stop means for limitingthe pivotal movement of the first arms with respect to the frame.
 12. Anapparatus according to claim 11 wherein the stop means are adjustable.13. An apparatus according to claim 1 wherein the stop means areadjustable.
 14. An apparatus according to claim 1 wherein each tie rodis pivotally connected to the frame at a position adjacent to andlaterally outside of the pivotal connection of the associated first armto the frame.
 15. An apparatus according to claim 14 wherein the tie rodis pivotally connected to the second arm at a position between the footpad and the pivotal connection of the second arm to the first arm. 16.An apparatus according to claim 15 wherein the tie rod is pivotallyconnected to the second arm adjacent a position midway between thepivotal connection of the second arm to the first arm and the foot pad.